Image locking system for DNA micro-array synthesis

Abstract

An image locking system for DNA micro-array synthesis provides a feedback system to stabilize or lock the image with respect to an image capture device, such as a camera and/or microscope. The image locking system includes the use of detection or reference marks. When a shift in image position is detected, a correction signal is sent to one of two mirrors, moving the image to correct for the shift in image position. The system comprises a first light beam directed towards a micromirror device that forms an alignment pattern on a reaction cell and a second light beam directed towards the micromirror device that forms a micro-array image on an active surface of the reaction cell. A camera captures the alignment pattern and an alignment mark. A computer calculates a correction signal to realign the alignment pattern with the alignment mark when movement is detected.

1. An image locking system for use in DNA micro-array synthesis, the system comprising:
 a reaction cell with an active surface on which a micro-array may be formed; 
 a micromirror device, the micromirror device formed of an array of electronically addressable micromirrors wherein each micromirror can be selectively tilted between one of at least two positions whereby a first light beam directed towards the micromirror device forms a micro-array image on the active surface of the reaction cell; 
 an alignment mark located at the reaction cell; 
 a second light beam that is directed towards the micromirror device thereby forming an alignment pattern on the reaction cell; 
 a camera capturing an alignment image, the alignment image comprising the alignment mark and the alignment pattern reflected onto the reaction cell; 
 a computer identifying a change in the alignment image and calculating a correction signal to remove the change from the alignment image; and 
 at least one actuator provided to adjust the alignment image in response to the correction signal calculated by the computer. 
 
     
     
       2. The system of  claim 1  wherein the micromirror device is formed of a two dimensional array of micromirrors. 
     
     
       3. The system of  claim 1  wherein the first light beam is provided by an ultraviolet lamp. 
     
     
       4. The system of  claim 3  wherein the ultraviolet lamp is a 1000 watt mercury arc lamp. 
     
     
       5. The system of  claim 3  wherein the ultraviolet lamp provides light with a wavelength in a range from 350 nanometers to 450 nanometers. 
     
     
       6. The system of  claim 5  wherein the ultraviolet lamp provides light with a wavelength of 365 nanometers. 
     
     
       7. The system of  claim 1  wherein the first light beam is provided by a visible wavelength lamp. 
     
     
       8. The system of  claim 1  wherein the second light beam is provided by a laser. 
     
     
       9. The system of  claim 8  wherein the laser is a He—Ne laser. 
     
     
       10. The system of  claim 9  wherein the He—Ne laser provides light with a wavelength of 632.8 nanometers. 
     
     
       11. The system of  claim 1  wherein the camera is a charge coupled device camera. 
     
     
       12. The system of  claim 1  wherein the at least one actuator is an electro-strictive actuator. 
     
     
       13. The system of  claim 12  wherein three electro-strictive actuators are provided. 
     
     
       14. The system of  claim 1  wherein the alignment image is formed by a microscope lens. 
     
     
       15. A method of forming an image locking system for use in DNA micro-array synthesis, the method comprising:
 projecting a first light beam towards a micromirror device that forms an initial alignment pattern; 
 reflecting the initial alignment pattern along an optical path and onto a reaction cell; 
 capturing an initial alignment image wherein the initial alignment image comprises an alignment mark and the initial alignment pattern projected onto the reaction cell; 
 projecting the first light beam towards the micromirror device that forms a current alignment pattern; 
 reflecting the current alignment pattern along the optical path and onto the reaction cell; 
 capturing a current alignment image wherein the current alignment image comprises the alignment mark and the current alignment pattern projected onto the reaction cell; 
 calculating the displacement between the initial alignment image and the current alignment image; and 
 sending a correction signal to at least one actuator to remove the displacement between the initial alignment image and the current alignment image. 
 
     
     
       16. The method of  claim 15 , wherein the first light beam is provided by a laser. 
     
     
       17. The method of  claim 16  wherein the laser is a He—Ne laser. 
     
     
       18. The method of  claim 17  wherein the He—Ne laser provides light with a wavelength of 632.8 nanometers. 
     
     
       19. The method of  claim 15  wherein projecting the first light beam towards the micromirror device further comprises selectively tilting an array of electronically addressable micromirrors that form the micromirror device wherein each micromirror can be tilted between one of at least two positions wherein a first position for a micromirror defines an on state for the micromirror whereby the first light beam is directed away from the optical path, and a second position for the micromirror defines an off state for the micromirror whereby the first light beam is directed towards the optical path. 
     
     
       20. The method of  claim 19  wherein the micromirror device is formed of a two dimensional array of micromirrors. 
     
     
       21. The method of  claim 19  further comprising forming a micro-array image on an active surface of the reaction cell by directing a second light beam to the micromirror device wherein the micromirror in the on state reflects the second light beam towards the optical path and the micromirror in the off state reflects the second light beam away from the optical path. 
     
     
       22. The method of  claim 21  wherein the micromirror device is formed of a two dimensional array of micromirrors. 
     
     
       23. The method of  claim 21  wherein the second light beam is provided by an ultraviolet lamp. 
     
     
       24. The method of  claim 23  wherein the ultraviolet lamp is a 1000 watt mercury arc lamp. 
     
     
       25. The method of  claim 23  wherein the ultraviolet lamp provides light with a wavelength in a range from 350 nanometers to 450 nanometers. 
     
     
       26. The method of  claim 25  wherein the ultraviolet lamp provides light with a wavelength of 365 nanometers. 
     
     
       27. The method of  claim 21  wherein the second light beam is provided by a visible wavelength lamp. 
     
     
       28. The method of  claim 15  further comprising forming the optical path using a reflective telecentric imaging system comprising a concave mirror and a convex mirror whereby the concave mirror receives light directed towards the optical path and reflects the light towards the convex mirror, the convex mirror receives the light from the concave mirror and reflects the light back towards the concave mirror, and the concave mirror receives the light redirected from the convex mirror and reflects the redirected light onto the reaction cell. 
     
     
       29. The method of  claim 28  further comprising moving the concave mirror in response to the correction signal with the at least one actuator. 
     
     
       30. A method of forming an image locking system for use in DNA micro-array synthesis, the method comprising:
 projecting a first light beam towards a micromirror device that forms an initial alignment pattern; 
 reflecting the initial alignment pattern along an optical path and onto a reaction cell; 
 capturing an initial alignment pattern image of the initial alignment pattern projected onto the reaction cell; 
 projecting the first light beam towards a micromirror device that forms a current alignment pattern; 
 reflecting the current alignment pattern along the optical path and onto the reaction cell; 
 capturing a current alignment pattern image of the current alignment pattern projected onto the reaction cell; 
 calculating the displacement between the initial alignment pattern image and the current alignment pattern image; and 
 sending a correction signal to at least one actuator to remove the displacement between the initial alignment pattern image and the current alignment pattern image. 
 
     
     
       31. The method of  claim 30  further comprising capturing an alignment mark image of an alignment mark located at the reaction cell. 
     
     
       32. The method of  claim 31  wherein calculating the displacement further comprises:
 calculating a first cross correlation between the alignment mark image and the current alignment image; 
 calculating a second cross correlation between the initial alignment pattern image and the current alignment image; 
 calculating a reference location from a peak of the first cross correlation; 
 calculating a current location from a peak of the second cross correlation; 
 calculating a displacement between the current location and the reference location. 
 
     
     
       33. The method of  claim 30 , further comprising forming the optical path using a reflective telecentric imaging system comprising a concave mirror and a convex mirror whereby the concave mirror receives light directed towards the optical path and reflects the light towards the convex mirror, the convex mirror receives the light from the concave mirror and reflects the light back towards the concave mirror, and the concave mirror receives the light redirected from the convex mirror and reflects the redirected light onto the reaction cell. 
     
     
       34. The method of  claim 33  further comprising moving the concave mirror in response to the correction signal with the at least one actuator. 
     
     
       35. The method of  claim 30 , wherein the first light beam is provided by a laser. 
     
     
       36. The method of  claim 35  wherein the laser is a He—Ne laser. 
     
     
       37. The method of  claim 36  wherein the He—Ne laser provides light with a wavelength of 632.8 nanometers. 
     
     
       38. The method of  claim 30  wherein projecting the first light beam towards the micromirror device further comprises selectively tilting an array of electronically addressable micromirrors that form the micromirror device wherein each micromirror can be tilted between one of at least two positions wherein a first position for a micromirror defines an on state for the micromirror whereby the first light beam is directed away from the optical path, and a second position for the micromirror defines an off state for the micromirror whereby the first light beam is directed towards the optical path. 
     
     
       39. The method of  claim 38  wherein the micromirror device is formed of a two dimensional array of micromirrors. 
     
     
       40. The method of  claim 38  further comprising forming a micro-array image on an active surface of the reaction cell by directing a second light beam to the micromirror device wherein the micromirror in the on state reflects the second light beam towards the optical path and the micromirror in the off state reflects the second light beam away from the optical path. 
     
     
       41. The method of  claim 40  wherein the micromirror device is formed of a two dimensional array of micromirrors. 
     
     
       42. The method of  claim 40  wherein the second light beam is provided by an ultraviolet lamp. 
     
     
       43. The method of  claim 42  wherein the ultraviolet lamp is a 1000 watt mercury arc lamp. 
     
     
       44. The method of  claim 42  wherein the ultraviolet lamp provides light with a wavelength in a range from 350 nanometers to 450 nanometers. 
     
     
       45. The method of  claim 44  wherein the ultraviolet lamp provides light with a wavelength of 365 nanometers. 
     
     
       46. The method of  claim 30  wherein the second light beam is provided by a visible wavelength lamp.